<!DOCTYPE html>
<html>
<meta charset="utf-8">
<title>Dynamic change to paint containment (reference)</title>

<style>
  #container {
      width: 100px;
      height: 100px;
      background: green;
      content-visibility: visible;
      contain: style;
  }
  #overflowing {
      width: 400px;
      height: 100px;
  }
  .square {
      display: inline-block;
      width: 50px;
      height: 50px;
      margin: 5px;
  }
  .green {
      background: green;
  }
</style>

<body>
  <p>PASS if you see <em>two</em> green squares.</p>
  <div id="container">
    <div id="overflowing"><div class="square"></div><div class="square"></div><div class="green square"></div></div>
  </div>
</body>
</html>
